Lipstatin is a potent, irreversible inhibitor of pancreatic lipase, a natural product that was first isolated from Streptomyces toxyricini. (Weibel et. al (1987) “Lipstatin, an inhibitor of pancreatic lipase, produced by Streptomyces toxytricini. I. Producing Organism, fermentation, isolation and biological activity” J Antibiotic (Tokyo) 40 (8): 1081-5. PMID 3680018. Lipstatin gained considerable importance as a key intermediate for the preparation of tetrahydrolipstatin (Orlistat) which is useful in the prophylaxis and treatment of diseases associated with obesity. E. Hochuli, et al describes the structural chemistry of lipstatin (Journal of Antibiotics Vol XL, No. 8 pp 1081-1085).
The fermentative process for its production, a process for its isolation from microorganisms and a process for its hydrogenation to tetrahydrolipstatin are known and described in U.S. Pat. No. 4,598,089. This invention uses a specific strain Streptomyces toxytricini NRRL 15443 and describes preparation of a two step vegetative inoculum.
EP 0803567 describes a fermentation process of lipstatin with the help of precursors such as linoleic acid, caprylic acid and N-formyl-L-leucine or leucine. The production of lipstatin is afforded by a streptomyces fermentation, process involving feeding of linoleic acid and leucine. Herein, leucine is incorporated into the final molecule whereas linoleic acid forms the backbone of the final molecule. This process typically gives a yield of lipstatin of about 20% (w/w) over the amount of linoleic acid fed.
WO 03/048335 describes another fermentation medium that uses oil in place of free fatty acid for the production of lipstatin.
Consequently, there remains a need for a low-cost, commercially viable fermentation process which provides sufficient nutrient support to the fermenting microorganism to permit high specific productivity of lipstatin from suitable fatty acid precursors or starting material.
Aside from the discussion above, nothing can be drawn from the literature concerning the use of a combination of linoleic acid with another omega-9 fatty acid to significantly enhance production levels of lipstatin. Unlike the methods suggested in the cited references above, the methods of the present invention provide the triple advantage of: (1) Permitting about 100% improvements in the yield coefficient of lipstatin; (2) Improvising productivity as well as the ease of operation (3) yielding a commercially viable process that is scalable.
Accordingly, an objective of the instant invention is to provide a commercially viable process for the production of lipstatin affording higher yields, an improvement of about 100% in yield coefficient and providing ease of operation as well.